Ok, I'm coming in a bit late but let me respond first to the original question. I can completely understand where the original poster is coming from. Aikiweb is a good example of an aikido board, polite, disciplined, respectful. Many MMA/BJJ dominated sites on the web have more than their fair share of arrogant boors doing alot of posturing. But my experience in the real world is quite diferent. Almost without exception, everyone I've met on the BJJ mat has been polite, helpful and eager to train and share while exhibiting respect. In fact if I'm being honest, I see more people with run away ego's in Aikido than I do in BJJ. Maybe something to do with the lack of competition so they never get called on it? Who knows. So yes, although I share your experience of the various groups on the internet, it is not reflected in real life.
As for incorporating grappling defences in Aikido? Hmmmm. I've been cross training for a little while. I do some of it in my garage with my Aikido students. Every now and again I come under some pressure to incorporate some of that into my aikido classes. Sometimes I will, maybe a single technique over several months worth of classes (e.g. arm drag to get you out of trouble, knee ride when uke doesn't roll on to their stomach from ikkyo). but at the end of the day I'm not sure it's up to me to do this. As long as we're being honest with people as to where the strategic gaps in our art are, they are free to go and fill those gaps as they wish, just as I have. They'll get much more benefit from going to a judo or bjj class than from me trying to incorporate those things into an aikido class. I've exposed them to some of it, everyone knows I do it and I think it's worthwhile, my work is done. It's up to them to take the next step.

"When your only tool is a hammer every problem starts to look like a nail"